Protective device for electric flatirons



Feb. 27, 1923.

W. T. HOOFNAGLE PROTECTIVE DEVICE FCR ELECTRIC FLATIRCNS Filed Feb. l0, 1921 -U WMV Anh-.i Flin I.)

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Patented Feb. 27, 1923.`

- UNITED STATES PATENT OFFICE.

WILLIAM T. HOOFNAGLE, OF GLEN RIDGE, NEW JERSEY.

PRDTECTIVE DVICE FOR ELECTRIC FLATIRONS.

To all whom t may cof/:cem:

Be it known that I, VILLIAM T. Hoor- NAGLE, a citizen of the United States, residing at Glen Ridge, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Protective Devices for Electric Flatirons, ot' which the following is a specification.

As electric Iflat irons are now made, the resistance or heating element of the iron is so Aproportioned that while the iron is in use, the heat absorbed by the fabric on which it is operating prevents excessive heating of the iron; but if the iron is allowed to stand idle, with the currentA on, it accumulates heat very rapidly, particularly if it rests upon an object which is a poor conductor of heat. In order to avoid fire and damage by overheated irons, it is customary to rest the iron on a metal support, and to cut off current from the iron when it is not in use; but a careless operator will sometimes rest the iron upon a combustible support, such as an ironing board or table, and fail to cut off the current, with the result that the iron becomes over-heated and sets fire to the suport. p The purpose of this invention is to provide means for automatically cutting off the current from the electric iron when the iron becomes over-heated, thereby preventing the possibility of setting fire to objects upon which it may be left standing. In carrying out the invention, I provide a fuse socket on or in the body of the iron, and arrange within this socket an ordinary fuse plug, having a fuse of the proper current carrying capacity to protect the internal circuit of the iron against excessive currents which may result from short circuits, and also so related to the body of the iron that the fuse will be heated by the iron and will melt when the latter becomes excessively hot.

In the accompanying drawing,

Fig. l is a longitudinal, central section through an electrically heated flat iron, having a fuse plug attachment; and,

Fig. 2 is a top lan view of the same, with the handle attac ing cord and cover plate removed, the heating element being shown in dotted lines.

Referring to the drawing, A indicates the iron comprising a 'metal base or bottom piece l, having an upturned `flange 1a, a resistance 2. embedded in insulating material 3 which rests upon the b ase, a metal plate 4, resting upon the insulating material, and a top plate 5, provided with a handle 6, the members 1,

4, and 5 being securedtov'ether by a screw "7;

The plate 4 carries insuIated metal connectors 8 and 9, having openings 8a and 9, adapted to receive the terminals 10 and 11 ot' an electric cord 12, through which current is supplied to the resistance or heating element. i

The base of the iron is of the usual form, except that I provide a rearward extension l", which is raised above the body of the base, as shown, and suppoi'ts a socket 13, of insulating material. This socket has oppositely projecting arms 13, which are secured by screws 14 to ears 15, which project from the flange la. The socket has an internal nietal shell 14, screw-threaded to re ceive an ordinary fuse plug b. The socket shown in the drawing is' open at its lower end, in order that the plug may engage a metal body 16 which is arranged below the socket; within a thin cup-shaped piece of insulating material 3a, which electrically insulates the body from the lbase of the iron but allows it to come close to the base so as to be heated thereby. The fuse plug has the usual externally threaded metal shell 17, adapted to make contact electrically with the shell in the socket and a base contact piece 18, adapted to rest aga-inst the metal body 16 when the plug is in the socket. The fuse 19,indicated in dotted lines, is arranged within the plug and connected to its shell and to its end contact, as usual. One end of the resistance 2 is connected to the connector 9, as shown in Fig. 2, and the other end of the resistance is connected to the plate 16, as shown at 16a. The metal shell 14 in the socket is connected to the connector 8 by a pin 20, extending through the wall of the socket, and a wire 21 connected between said pin and said connector.

Vhen the cord is connected to the iron and the current is turned on, the current flows in a circuit extending from the connector 9 through the resistance 2 to the plate 16, thence through the contact 18 at the base of the fuse plug and through the fuse to the shell of the plug, thence to the shell of the socket, and thence through connections 20 and 21 to the connector 8. When the iron is in use, it does not become excessively hot because this heat is dissipated in the fabrics onwhich it is operating. lf the iron. isy allowed to stand, in one spot, with the current on, the iron becomes excessively hot', particularly if the support upon Whichit is placed is a poor conductor of heat such as wood or cloth. This accumulation of hea-t in the base causes the plate 1G also to become very hot7 and as the contact piece 18 of the fuse plug rests upon this plate, the latter also, and the fuse connected to it, will become excessively hot and the fuse will melt and interrupt the electric circuit when the temperature of the fuse reaches the melting point. rlihus, the current will be cut oil and the iron will cool1 ln order to use the iron agaim it will be necessary te place a new fuse plug in the socket. lf, While the current is applied to the iron, a short circuit occurs in its internal circuit which includes the 'use, the latter will blow and cut o the current.1

What l claim is:

1. ln an electric flat iron, a heating resistance and a metal body, in series with the i-,aamac resistance, adapted to be heated by the iron, a socket of insulating material mounted on the iron and having an internal threaded contact shell, and a hollow fuse plug having a threaded side contact engaging said shell, a base contact engaging said body and ay fuse Within the plug connected to said. side and base contacts.

2. ln an electric flat iron, a heating resistance and a metal body, in series With the resistance, adapted to be heated by the iron, a socket of insulating material mounted on the iron and having an internal threaded contact shell, said socket having its lower end open, and a hollow fuse plug extending through the socket to said body, said plug having a threaded side contact engaging said shell, a base Contact engaging said body, and a fuse Within the plug connected to said side and base contacts..

ln testimony whereof l allix my signature.

WILLIAM T. HOOFNAGLE. 

